Empedobacter tilapiae sp. nov., isolated from an intestine of Nile tilapia (Oreochromis niloticus).

Abstract

A Gram-stain-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, MRS2T, was isolated from an intestine of Nile tilapia (Oreochromisniloticus) collected from the Republic of Korea. Strain MRS2T grew optimally at 30 °C and in the presence of 0-2.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain MRS2T clustered with the type strains of Empedobacter species. It exhibited the highest 16S rRNA gene sequence similarity (98.5 %) to the type strain of Empedobacter falsenii and sequence similarities of 97.4-97.6 % to the type strains of two other Empedobacter species. Strain MRS2T contained MK-6 as the predominant ubiquinone and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C17 : 0 3-OH and iso-C15 : 0 as the major fatty acids. The major polar lipids of strain MRS2T were phosphatidylethanolamine, one unidentified lipid and one unidentified aminolipid. The DNA G+C contents of strain MRS2T were 32.2 mol% or 30.65 mol%. Strain MRS2T exhibited DNA-DNA relatedness values of 12-20 % to the type strains of Empedobacter falsenii, Empedobacter brevis and Empedobacter stercoris. The average nucleotide identity values between strain MRS2T and five strains of E. falsenii and E. brevis were 84.8-91.0 %. The phylogenetic, genetic and differential phenotypic properties indicated that strain MRS2T is separated from Empedobacter species. On the basis of the data presented here, strain MRS2T is considered to represent a novel species of the genus Empedobacter, for which the name Empedobactertilapiae sp. nov. is proposed. The type strain is MRS2T (=KCTC 62904T=NBRC 113550T).